Products from stevia rabaudiana

ABSTRACT

Various organic molecules, ingredients and compositions are prepared from Stevia rebaudiana plant. The compositions can be used as bulking agents, and sweeteners in foods, beverages, cosmetics and pharmaceuticals.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/172,525, filed Jun. 8, 2015, and this application is acontinuation-in-part application of: U.S. patent application Ser. No.14/195,812 entitled “Products From Stevia Rebaudiana”, filed Mar. 3,2014; U.S. patent application Ser. No. 13/943,776 entitled “FoodIngredients From Stevia Rebaudiana”, filed Jul. 16, 2013; which claimsthe benefit U.S. patent application Ser. No. 13/530,113 filed Jun. 22,2012 (now U.S. Pat. No. 8,530,527); which claims the benefit under 35U.S.C. 119(e) of U.S. Provisional Application No. 61/500,598 entitled“Food Ingredients From Stevia Rebaudiana”, filed Jun. 23, 2011; each ofwhich are herein incorporated by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to a process for producing food ingredients andother products from Stevia rebaudiana plant biomass and their use invarious applications including food products and beverages.

BACKGROUND OF THE INVENTION

Nowadays sugar alternatives are receiving increasing attention due toawareness of many diseases in conjunction with consumption of high-sugarfoods and beverages. However many artificial sweeteners such as dulcin,sodium cyclamate and saccharin were banned or restricted in somecountries due to concerns on their safety. Therefore non-caloricsweeteners of natural origin are becoming increasingly popular. Thesweet herb Stevia rebaudiana Bertoni produces a number of diterpeneglycosides which feature high intensity sweetness and sensory propertiessuperior to that of many other high potency sweeteners.

The above-mentioned sweet glycosides have a common aglycon, steviol, anddiffer by the number and type of carbohydrate residues at the C13 andC19 positions. The leaves of Stevia are able to accumulate up to 10-20%(on dry weight basis) steviol glycosides. The major glycosides found inStevia leaves are rebaudioside A (2-10%), stevioside (2-10%), andrebaudioside C (1-2%). Other glycosides such as rebaudioside B, D, E,and F, steviolbioside and rubusoside are found at much lower levels(approx. 0-0.2%).

Methods for the extraction and purification of sweet glycosides from theStevia rebaudiana plant using water or organic solvents are describedin, for example, U.S. Pat. Nos. 4,361,697; 4,082,858; 4,892,938;5,972,120; 5,962,678; 7,838,044 and 7,862,845.

As it is well known the use of high intensity sweeteners in variousapplications requires various bulking agents to substitute the sugarwhich is removed from the formulation. The bulking agents used in thoseapplications include both caloric and non-caloric materials. Nonlimiting examples of bulking agents include fructooligosaccharides,inulin, inulooligosaccharides, maltooligosaccharides, maltodextins,cyclodextrins, corn syrup solids, erythritol and other sugar alcohols,glucose, maltose, lactose, tagatose, lactulose, palatinose, isomalt,modified starches etc.

Obviously more preferable are the bulking agents which provide zerocalories, such as erythritol, isomalt, fructooloigosacharides, inulinetc.

On the other hand it has to be noted that steviol glycosides arecompounds extracted from the plant and in process of their manufacturelarge amounts of “empty” biomass is created. Moreover, generally, theextraction process utilizes only the Stevia plant leaves. Thisadditionally generates large amount of the stems which have limited useas well. The “empty” biomass is mainly discharged directly toenvironment. in some cases it is used for biogas production. It might beused as biofertilizer as well. The stems are generally used as fuel.

There is no reports to-date on processing the stevia biomass into anyfood ingredient. Nevertheless, if accomplished in large scale, this canprovide significant economic, and environmental benefits as it canprovide an opportunity for inclusion of whole stevia plant into foodchain, creating practically wasteless stevia processing.

Within the description of this invention we will show that, stevia plantbiomass may be used as a source for producing valuable food ingredientsand other chemicals, which can be used in number of areas including foodand beverage applications.

SUMMARY OF THE INVENTION

The present invention is aimed to overcome the disadvantages of existingStevia industrial processing schemes. The invention describes a processfor producing high value products and food ingredients from the Steviarebaudiana plant biomass and use thereof in various food products andbeverages as a carrier or bulking agent.

The invention, in part, pertains to high value products comprisingcellulose, or cellulose containing biomass derived from Steviarebaudiana Bertoni plant.

In the invention, Stevia rebaudiana Bertoni plant biomass, particularlythe leaves and/or stems, were used as a starting material.

The starting material was subjected to size reduction, by means ofrotary blade milling machine. The grinded biomass was subjected towater-soaking and alkaline pulping to obtain a pulp comprising of highcontent of cellulose, where the pulp can be used to produce for exampleglucose for further applications.

The pulp and/or any derivative thereof can be used as a feedstock formicroorganism(s) for de novo biosynthesis of steviol glycosidesmolecules. Such steviol glycoside molecules can be considered as“stevia-derived”, in contrast to current biosynthetic technology whichsynthesizes steviol glycoside molecules by recombinant microorganismsusing non-stevia feedstock (e.g. cane sugar, corn starch, etc).

In addition, the pulp can be further processed by bleaching and acidhydrolysis and spray drying to produce a microcrystalline cellulosecomplying to specifications prepared at the 55th JECFA (2000) andpublished in FNP52 Add 8 (2000), where the microcrystalline cellulosecan be used to produce for example glucose for further applications.

The obtained products are applicable to various foods and beverages asbulking agent, including tabletop sweeteners, soft drinks, ice cream,cookies, bread, fruit juices, milk products, baked goods andconfectionary products.

Preferably the product of invention is used with other sweeteners,flavors and food ingredients.

Non-limiting examples of sweeteners include steviol glycosides,stevioside, rebaudioside A, rebaudioside B, rebaudioside C, rebaudiosideD, rebaudioside E, rebaudioside F, rebaudioside G, rebaudioside H,rebaudioside I, rebaudioside J, rebaudioside K, rebaudioside L,rebaudioside M, rebaudioside N, rebaudioside O, rebaudioside P,rebaudioside Q, rebaudioside R, rebaudioside Z, dulcoside A,steviolbioside, rubusoside, as well as other steviol glycosides found inStevia rebaudiana plant and mixtures thereof, stevia extract, Luo HanGuo extract, mogrosides, high-fructose corn syrup, corn syrup, invertsugar, fructooligosaccharides, inulin, allulose, tagatose,inulooligosaccharides, coupling sugar, maltooligosaccharides,maltodextrins, corn syrup solids, glucose, maltose, sucrose, lactose,aspartame, saccharin, sucralose, sugar alcohols.

The obtained products are also used as starting material for preparationof glucose, dextrose, ethyl alcohol, various polymers and other organiccompounds.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

DETAILED DESCRIPTION OF THE INVENTION

Advantages of the present invention will become more apparent from thedetailed description given hereinafter. However, it should be understoodthat the detailed description and specific examples, while indicatingpreferred embodiments of the invention, are given by way of illustrationonly, since various changes and modifications within the spirit andscope of the invention will become apparent to those skilled in the artfrom this detailed description.

In the invention, Stevia rebaudiana plant biomass, particularly theleaves and stems of Stevia rebaudiana plant, were used as a startingmaterial. Other parts of Stevia rebaudiana plant can be used as well.The “empty” leaf biomass obtained after extraction of steviolglycosides, as well as Stevia rebaudiana plant stems remaining after“stripping-off” the leaves can be used as a starting material. Thestevia biomass suitable for the process of the present inventionincludes processed Stevia rebaudiana plants (e.g., post-extraction ofsteviol glycosides) and parts thereof as well as un-processed Steviarebaudiana plants and parts thereof.

The testing of obtained microcrystalline cellulose was conductedaccording to procedures set in microcrystalline cellulose monographprepared at the 55th FAO/JECFA meeting (2000) and published in Food andNutrition Paper 52 Addendum 8(2000).

The testing of obtained powder cellulose was conducted according toprocedures set in powder cellulose monograph prepared at the 20th JECFA(1976), published in FNS 1B (1977) and in FNP 52 (1992).

In one embodiment of the invention, the starting material is milledusing rotary blade grinder to produce particles from 1-50 mm, preferably5-20 mm in length. Any other equipment capable of reducing largeparticles into smaller ones can be used in this stage as well.

In one embodiment of the invention the obtained grinded biomass isdispersed in the water and boiled at 100° C. for 0.5-3 hours, preferably1-1.5 hours, followed by separation of the liquid and thewater-insoluble stevia biomass. The process is repeated several timesuntil colorless or substantially colorless liquid is obtained. Acontinuous extracting apparatus, as well as any other equipment known tothose skilled in art, may be used for this purpose.

In one embodiment of this invention the separated stevia biomass issubsequently introduced into 10-20% NaOH aqueous solution. The solutionis treated in pressurized vessel at 110-180° C., preferably 120-170° C.,during 0.1-10 hours, preferably 1-5 hrs to produce pulped biomass. Otheralkaline solutions can be used as well for this pulping step.

Alternatively other pulping techniques such as biological or organicsolvent pulping, mechanical, thermomechanical, chemo-thermomechanical,chemical pulping such as Kraft process, sulfite process can be used.After thermal treatment the pulped biomass is separated from the liquidand washed with water till neutral pH of washing water is achieved.

In one embodiment of this invention the washed biomass is optionallytreated with bleaching agent. Various bleaching agents such as hydrogenperoxide, ozone, chlorine, sodium hypochlorite, chlorine oxide, enzymesmay be used. However it is preferred to use chlorine-free bleachingagents.

In one embodiment of present invention the bleaching of pulped biomassis achieved by using 10-30%, preferably 20-25%, hydrogen peroxide. Thebiomass was suspended in 0.5-5, preferably 1-3 volumes of hydrogenperoxide and incubated at 80-150° C., preferably 100-120° C., during0.1-3 hours, preferably 0.5-1.5 hours. The bleached biomass wassubsequently separated from liquid and washed with water.

In one embodiment of this invention, the obtained biomass was subjectedto partial depolymerization. Mechanical depolymerization(disintegration) and/or various agents capable of depolyimerizing thecellulose, such as mineral acids and enzymes, can be utilized for thisstage.

In one embodiment of this invention the depolymerization is achieved by1-20%, preferably 5-15% hydrochloric acid. The ratio of bleached biomassto acid solution is 1:0.5 to 1:5, preferably 1:1 to 1:3. The temperatureof depolymerization process is 50-120° C., preferably 80-100° C. during0.1-5 hours, preferably 0.5-2 hours.

In one embodiment the obtained depolymerized cellulose is separated fromacid solution and washed with water until neutral pH is achieved. Theobtained solids are suspended in 1-3 volumes of water and spray dried atinlet temperature of 180° C. and outlet temperature of 100° C.

In one embodiment of this invention the cellulose is mechanicallydisintegrated to produce powder cellulose (INS 460ii).

In one embodiment of present invention a stevia sweetener is added todepolymerized cellulose slurry. The ratio of stevia sweetener todepolymerized cellulose on dry weight basis is 1:50 to 1:400 (wt),preferably 1:100 to 1:300.

Any other drying techniques such as flash drying, or vacuum drying canbe used for the drying of the slurry as well.

Non-limiting examples of stevia sweeteners include stevia extract,steviol glycosides, stevioside, rebaudioside A, rebaudioside B,rebaudioside C, rebaudioside D, rebaudioside E, rebaudioside F,rebaudioside G, rebaudioside H, rebaudioside I, rebaudioside J,rebaudioside K, rebaudioside L, rebaudioside M, rebaudioside N,rebaudioside O, rebaudioside P, rebaudioside Q, rebaudioside R,rebaudioside Z, dulcoside A, steviolbioside, rubusoside, as well asother steviol glycosides found in Stevia rebaudiana plant and mixturesthereof.

Alternatively the cellulose produced by the method of this invention canbe processed into other food ingredients by techniques known to thoseskilled in art. Non-limiting examples of such ingredients include, watersoluble cellulose, carboxymethyl cellulose, methylcellulose,hydroxypropylcellulose, hydroxypropyl-methylcellulose,ethyl-methylcellulose as well as cellobiose, glucose etc.

Alternatively the cellulose containing materials produced by the methodof this invention can be processed into other chemicals and products bytechniques known to those skilled in art. Non limiting examples of suchtechniques include, mechanical processing (crushing, milling, grinding,pressing, drying, disintegrating, etc), chemical/enzymatic hydrolysis,biotransformation, fermentation (including fermentation by recombinantmicroorganisms or genetically modified microbial host cells), chemicalsynthesis, biocatalysis, chemical catalysis, bioconversion,biodegradation, derivatization, polymerization, chemical/enzymaticisomerization, etc. Non limiting examples of organic chemicals include,monosaccharides, oligosaccharides, polysaccharides, alcohols, polyols,organic acids, carboxylic acids and salts thereof, biofuels,biodegradable polymers, recyclable polymers, food grade polymers,packaging materials, inks, various grades of paper, ethanol, PET,polyethylene terephthalate, monoethylene glycol, MEG, ethylene glycol,ethylene, terephthalic acid, lactic acid, etc.

In one particular embodiment the cellulose containing materials producedby the method of this invention are useful as stevia-derived feedstock,including but not limited to pulp, bleached pulp, purified cellulose,hydrolyzed cellulose, depolymerized cellulose, disintegrated cellulose,dextrose, which is contacted with recombinant microorganism(s) toproduce steviol glycosides. Non limiting examples of steviol glycosidesinclude stevioside, rebaudioside A, rebaudioside B, rebaudioside C,rebaudioside D, rebaudioside E, rebaudioside F, rebaudioside G,rebaudioside H, rebaudioside I, rebaudioside J, rebaudioside K,rebaudioside L, rebaudioside M, rebaudioside N, rebaudioside O,rebaudioside P, rebaudioside Q, rebaudioside R, rebaudioside Z,dulcoside A, steviolbioside, rubusoside, alpha-glucosylated steviolglycosides, as well as other steviol glycosides found in Steviarebaudiana plant and mixtures thereof.

The products of present invention can be used as bulking agents,sweeteners, flavor enhancers in various food and beverage products.Non-limiting examples of food and beverage products include tabletopsweeteners, carbonated soft drinks, flavored carbonated soft drinks,cola flavored carbonated soft drinks, lemon lime flavored carbonatedsoft drinks, low-calorie carbonated soft drinks, zero-calorie carbonatedsoft drinks, ready to drink beverages, energy drinks, isotonic drinks,low-calorie drinks, zero-calorie drinks, sports drinks, teas, fruit andvegetable juices, juice drinks, dairy drinks, yoghurt drinks, alcoholbeverages, powdered beverages, bakery products, cookies, biscuits,baking mixes, cereals, confectioneries, candies, toffees, chewing gum,dairy products, flavored milk, yoghurts, flavored yoghurts, culturedmilk, soy sauce and other soy base products, salad dressings,mayonnaise, vinegar, frozen-desserts, meat products, fish-meat products,bottled and canned foods, fruits and vegetables.

Additionally the products can be used in drug or pharmaceuticalpreparations and cosmetics, including but not limited to toothpaste,mouthwash, cough syrup, chewable tablets, lozenges, vitaminpreparations, and the like.

The products can be used “as-is” or in combination with othersweeteners, flavors and food and beverage ingredients.

Non-limiting examples of sweeteners include steviol glycosides,stevioside, rebaudioside A, rebaudioside B, rebaudioside C, rebaudiosideD, rebaudioside E, rebaudioside F, rebaudioside G, rebaudioside H,rebaudioside I, rebaudioside J, rebaudioside K, rebaudioside L,rebaudioside M, rebaudioside N, rebaudioside O, rebaudioside P,rebaudioside Q, rebaudioside R, rebaudioside Z, dulcoside A,steviolbioside, rubusoside, as well as other steviol glycosides found inStevia rebaudiana plant and mixtures thereof, stevia extract, Luo HanGuo extract, mogrosides, high-fructose corn syrup, corn syrup, invertsugar, fructooligosaccharides, inulin, inulooligosaccharides, couplingsugar, maltooligosaccharides, maltodextrins, corn syrup solids, glucose,maltose, sucrose, allulose, tagatose, lactose, aspartame, saccharin,sucralose, sugar alcohols.

Non-limiting examples of flavors include lemon, orange, fruit, banana,grape, pear, pineapple, bitter almond, cola, cinnamon, sugar, cottoncandy, vanilla flavors.

Non-limiting examples of other food ingredients include flavors,acidulants, organic and amino acids, coloring agents, bulking agents,modified starches, gums, texturizers, preservatives, antioxidants,emulsifiers, stabilisers, thickeners, gelling agents, caffeine.

The following examples illustrate various embodiments of the invention.It will be understood that the invention is not limited to thematerials, proportions, conditions and procedures set forth in theexamples, which are only illustrative.

EXAMPLE 1

Preparation of Stevia Ingredient

1 kg of Stevia rebaudiana plant dried leaves were grinded into pieces ofapprox 10 mm, suspended in 5 L of water and boiled for 1 hour. Theliquid was removed and the separated biomass was resuspended in thewater and treated as described above. The process was repeated 5 times.The resulted biomass was suspended in 3 L 15% NaOH solution and placedinto autoclave for pulping at 150° C. for 2 hrs. The obtained pulpedbiomass is separated from liquid and washed with deionized water tillneutral pH of washing water. The washed pulp was suspended in 3 L of 20%hydrogen peroxide and treated for 1 hr at 100° C. The bleached pulp waswashed with water and suspended in 3 L 10% hydrochloric acid. Themixture was heated to 90° C. for 1 hr. The obtained mixture was strainedthrough 60 mesh sieve and then filtered through grade 1 filter paper.The solids recovered on the filter paper were washed with deionozedwater till neutral pH of washing water was achieved. The washed weresuspended in 1.5 L of water and spray dried by YC-015 laboratory spraydrier (Shanghai Pilotech Instrument & Equipment Co. Ltd., China)operating at 180° C. inlet and 100° C. outlet temperature. About 480 gof free flowing microcrystalline cellulose was obtained.

EXAMPLE 2

Preparation of Stevia Ingredient

1 kg of Stevia rebaudiana plant dried stems were processed similarly toleaves according to EXAMPLE 1. About 670 g of free flowingmicrocrystalline cellulose was obtained.

EXAMPLE 3

Preparation of Stevia Composition

About 500 g of microcrystalline cellulose prepared according to example1 or 2 was added to 1500 mL water solution containing 2.5 g ofrebaudioside A produced by PureCircle Sdn. Bhd. (Malaysia) with purityof 99.5% (dry basis). The mixture was spray dried to yield about 490 gof dry powder.

EXAMPLE 4

Preparation of Pulp from Stevia Plant

1 kg of Stevia rebaudiana plant dried stems were grinded into pieces ofapprox 10 mm, suspended in 5 L of water and boiled for 1 hour. Theliquid was removed and the retained biomass was suspended in 6 L 20%NaOH solution and placed into digester for pulping at 170° C. for 2 hrs.The obtained pulped biomass is separated from liquid and washed withdeionized water. The washed pulp was reduced in a homogenizer to yield400 g of unbleached pulp. The analysis results show 99.2% carbohydratecalculated as cellulose on dry basis, and 0.08% sulfated ash content(Microcrystalline Cellulose, FAO Food and Nutrition Paper 52 Addendum8(2000)).

EXAMPLE 5

Preparation of Glucose from Pulp

10 g of unbleached pulp prepared according to EXAMPLE 4 was suspended in500 mL of 5% H₂SO₄ solution and incubated at 100° C. for 2 hours. Thereaction was stopped by neutralizing the reaction mixture with 20% NaOH.The obtained solution was passed through columns packed with AmberliteFPC23H and Amberlite FPA51 ion exchange resins and the glucoseconcentration was determined by Somogyi-Nelson reducing sugar method(Somogyi, M. (1952). J. Biol. Chem., 200, 245). The yield of glucose was52%.

EXAMPLE 6

Preparation of Glucose from Pulp

10 g of unbleached pulp prepared according to EXAMPLE 4 was mixed with100 mL 0.5% H₂SO₄ and incubated at 100° C. for 20 min. Then the pulp waswashed with water until neutral pH. The washed pulp was mixed with 200mL of water, 250 FPU of “Cellulase GC 220®” (Genencor, USA), 750 IU of“Novozyme 188®” β-glucosidase (Novozymes, Denmark), and the reaction wasconducted at pH 5.0 and 50° C. for 4 8hrs. The reaction was stopped byboiling for 10 min at 100° C. The glucose concentration was determinedby Somogyi-Nelson reducing sugar method (Somogyi, M. (1952). J. Biol.Chem., 200, 245). The yield of glucose was 82%.

EXAMPLE 7

Fermentation of Glucose to Ethanol

10 L of glucose solution prepared according to EXAMPLE 6 wasconcentrated to 10% solids content and fermented with Saccharomycescerevisiae St-50 (Culture Collection of PureCircle Sdn. Bhd., Malaysia)at 28° C. during 24 hrs. The Ethanol from fermented solution wasrecovered by distillation to obtain 260 mL of 95% (v/v) Ethanol.

It is to be understood that the foregoing descriptions and specificembodiments shown herein are merely illustrative of the best mode of theinvention and the principles thereof, and that modifications andadditions may be easily made by those skilled in the art withoutdeparting for the spirit and scope of the invention, which is thereforeunderstood to be limited only by the scope of the appended claims.

We claim:
 1. A process for producing a stevia-derived feedstock,comprising the steps of (a) providing a water-insoluble stevia biomass;(b) incubating the water-insoluble stevia biomass in an alkalinesolution to produce a cellulose containing material; (c) processing thecellulose containing material to provide the stevia-derived feedstock.2. The process of claim 1, wherein the cellulose containing material isprocessed to produce one or more selected from the group consisting of:pulp, bleached pulp, purified cellulose, hydrolyzed cellulose,depolymerized cellulose, disintegrated cellulose, dextrose, andcombinations thereof.
 3. The process of claim 1, wherein thewater-insoluble stevia biomass is produced by milling Stevia rebaudianaplant biomass materials and boiling the plant biomass in water.
 4. Aprocess of producing a stevia ingredient, comprising the steps ofcontacting the stevia-derived feedstock made by the process of claim 1with a recombinant microorganism.
 5. The process of claim 4, wherein thestevia ingredient is selected from the group consisting of: stevioside,rebaudioside A, rebaudioside B, rebaudioside C, rebaudioside D,rebaudioside E, rebaudioside F, rebaudioside G, rebaudioside H,rebaudioside I, rebaudioside J, rebaudioside K, rebaudioside L,rebaudioside M, rebaudioside N, rebaudioside O, rebaudioside P,rebaudioside Q, rebaudioside R, rebaudioside Z, dulcoside A,steviolbioside, rubusoside, alpha-glucosylated steviol glycosides,steviol glycosides found in Stevia rebaudiana plant, and combinationsthereof.
 6. The process of claim 4, further comprising the step ofcombining the stevia ingredient with a food, beverage, drug,pharmaceutical, cosmetic or consumable product.
 7. The process of claim4, further comprising the step of combining the stevia ingredient with astevia-derived cellulose.
 8. The process of claim 7, wherein thestevia-derived cellulose is obtained from a second water-insolublestevia biomass.
 9. The process of claim 8, wherein the secondwater-insoluble stevia biomass is treated with an alkaline solution andbleached to form the stevia-derived cellulose.